There is known a game device in which a screen coordinate value (coordinate value in a screen coordinate system) is acquired according to a user's operation to advance a game based on the screen coordinate value. For example, there is known a game device in which a game is advanced based on a screen coordinate value input by using a mouse, a touch panel, or a pointing device such as an information input device disclosed in Patent Document 1.    Patent Document 1: JP3262677B